This study will develop and test intervention strategies to prevent alcohol and other substance abuse among high-risk youth. The study has three aims: 1) Develop intervention strategies to prevent alcohol and other substance abuse among high-risk youth. 2) Test the strategies in a randomized trial with high-risk youth in community settings. 3) Develop and deliver booster sessions to extend and expand intervention effects. 4) Longitudinally evaluate the strategies through follow-up data collections. 5) Analyze relationships among individual-level variables for youth and parent participants. The proposed study will occur in three phases. In a 10-month preparation phase, the investigators will develop intervention and measurement protocols, draw a representative sample of community organizations for study participation, and recruit and train intervention delivery agents. A 12-month implementation phase will initiate field operations of a clinical trial, including pretesting, intervention delivery, process data collection, and posttesting. A follow-up phase in the last years of the study will involve follow-up testing, booster session delivery, and data analysis. The study's alcohol and other substance abuse prevention strategy includes skills interventions that will engage groups of high-risk youths in community settings, and parent-enhanced skills intervention that will help family members sustain youths' risk reduction efforts. By engaging parents in the skills-based intervention, the prevention protocol will tap natural resources in youths' environments to nurture and sustain their efforts to avoid problems with alcohol and other substance abuse.